Tutorial 4

Chapter 4The Components ofthe System Unit

Chapter 4 ObjectivesChapter 4 Objectives

Describe the componentsin the system unit

Explain how the CPU uses the four steps of a machine cycle

to process data

Compare and contrast various personal computer processors

on the market today

Define a bit and describe how a series of bits represents data

Differentiate among thevarious types of memory

Explain the difference between a serial, a parallel,

and a USB port

Describe how busescontribute to a computer’s

processing speed

Describe the typesof expansion slots and cards

in the system unit

Identify componentsin a notebook computer

Identify componentsin a handheld computer

p. 4.2

Next

The System UnitThe System Unit

Box-like case that contains computer’s electronic components

Sometimes called the chassis

What is the system unit?

p. 4.2 Fig. 4-1

Next

Processor Memory module

Processor Memory module Expansion cards

• Sound card• Modem card• Video card• Network

interface card

Ports and Connectors


• Sound card


• Sound card• Modem card


• Sound card• Modem card• Video card


• Sound card• Modem card• Video card• Network

interface card

Processor


What are common components insidethe system unit?

p. 4.3 Fig. 4-2

Next


What is the motherboard?

Click to view Web Link then click Motherboards

Click to view animation

Main circuit boardin system unit

Containschips,integrated circuits,and transistors

Also calledsystem board

p. 4.4 Fig. 4--3

Next

http://scsite.com/dc2003/ch4/weblink.htm

dual inline package (DIP)


What chip packages are available?

pin grid array (PGA)

single edge contact (SEC) cartridge

flip chip-PGA (FC-PGA) package

p. 4.4 Fig. 4-4

Next

Click to view video

Central Processing UnitCentral Processing Unit

What is the central processing unit (CPU) ? Interprets and carries out basic instructions that operate

a computer Also called

the processor

p. 4.5 Fig. 4-5

Next

CPU


What are the components of the CPU?

CPU

Arithmetic/Logic Unit

(ALU)

Control Unit

p. 4.5

Next


What is the control unit?

Control Unit

Control unit repeatsfour basic operations:

Fetch - obtain program instruction or data item from memory

Decode - translate instruction into commands

Execute - carry out command Store - write result to memory

Directs and coordinates operations in computer

p. 4.5

Next

Four operations of the CPU comprise a machine cycleAlso called instruction cycle

• Execution time (e-time) - time taken to execute and store

e-time

• Instruction time (i-time) - time taken to fetch and decode

i-time


What is a machine cycle?

p. 4.6

Next


Student enters math problem (100 x 52) into computer’s memory

Result in memory displays on monitor’s screen

An example of a machine cycle

p. 4.6 Fig. 4-6

Next

100 x 52


How is the CPU’s speed measured? According to

how many millions of instructions per second (MIPS) it can process

p. 4.6

Next

CISC(complex instruction set

computing) Supports large number

of instructions CPU executes complex

instructions more quickly

Central Processing Unit

What are two designs used for the CPU?

RISC(reduced instruction

set computing) Supports smaller

number of instructions

CPU executes simple instructions more quicklyp. 4.6

Next

Comparison (greater than, equal

to, or less than)

Arithmetic (addition, subtraction,

multiplication, and division)

What is the arithmetic/logic unit (ALU) ?


.and.

.and.

.not.

.not..or..or.Logical (AND, OR,

NOT)p. 4.7

Next

CPU component that performs execution part of the machine cycle


What is pipelining?

Machine Cycle (without pipelining)

Machine Cycle (with pipelining)

Instruction 1

Instruction 2

Instruction 3

Instruction 4

CPU begins executing second instruction before completing first instruction

Results in faster processing

p. 4.7 Fig. 4-7

Next

What is a register?


Stores location from where

instruction was fetched

Stores instruction while it is

being decoded

Stores data while ALU processes it

Stores results of calculation

p. 4.7

Next

Temporary storage area that holds data and instructions


What is the system clock?

MHz - one million ticks of system clock

GHz – one billion ticks of system clock

Click to view Web Link

then click Clock Speed

p. 4.8

Next

Synchronizes all computer operations

Each tick is clock cycle



What is a microprocessor?Single processor chip found

in personal computers


then click Processors

Click to view animation

p. 4.9

Next


p. 4.9 Fig. 4-10


How do personal computer processors compare?

Next


One type is a floating-point coprocessor,

also known as a math or numeric

coprocessor

Chip that assists processor in performing

specific tasks

What is a coprocessor?

p. 4.13

Next


What is parallel processing?Using multiple processors

simultaneously to execute program faster

Requires special software to divide problem and bring results togetherp. 4.13 Fig. 4-13

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Data RepresentationData Representation

How do computers represent data? Most computers are digital

Recognize only two discrete states: on or off

1 1 1 1 1

0 0 0 0 0

on

offp. 4.13

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What is the binary system?

Binary Digit (bit)

Electronic Charge

Electronic State

Number system with two unique digits: 0 and 1

p. 4.14 Fig. 4-14

Next


What is a byte?

8-bit byte for the number 3

8-bit byte for the number 5

8-bit byte for the capital letter T

Eight bits grouped together

p. 4.14 Fig. 4-15

Next


What are three popular coding systems to represent data? ASCII - American

Standard Code for Information Interchange

EBCDIC - Extended Binary Coded Decimal Interchange Code

Unicode - coding scheme capable of representing all world’s languages

p. 4.14 Fig. 4-16

Next

Step 2: Electronic signal for letter T sent to system unit

Step 3: Signal changed to its ASCII code (01010100) and stored in memory

Step 4: After processing, binary code for letter T is converted to image on output device


How is a character sent from keyboard to computer?

Step 1: Press letter T

p. 4.15 Fig. 4-17

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MemoryMemory

What is memory?

Temporary storage area for operating system, application programs, and data

Consists of one or more chips on motherboard

Each byte stored in unique address

p. 4.15

Next

seat C22

seat B22

seat A22

MemoryMemory

How is memory measured?By number of bytes available

p. 4.16 Fig. 4-19

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volatile memoryLoses its contents when Loses its contents when the computer's power is the computer's power is

turned offturned off

volatile memoryLoses its contents when

computer's poweris turned off

MemoryMemory

What are two types of system unit memory?

nonvolatile memory

Does NOT lose its contents when

computer’s power is turned off

p. 4.16

Next

MemoryMemory

What is random access memory (RAM)?

p. 4.16

Next

Memory chips that can be read from and written to by processor

Most RAM is volatileThe more RAM a computer has, the faster it

operates

memory module

MemoryMemory

What are two basic types of RAM chips?

Dynamic RAM (DRAM) Most common type Also called main memory

Static RAM (SRAM) Used for special

applications such as cache

Faster and more reliable than DRAM chipsp. 4.18

Next

MemoryMemory

Software package usually indicates RAM requirements

How much RAM is needed?

p. 4.18 Fig. 4-22

Next

p. 4.19 Fig. 4-23

MemoryMemory

How much RAM is needed? Depends on type of applications you intend to

run on your computer

Next

MemoryMemory

What is cache? Helps speed computer

processes by storing frequently used instructions and data

Also called memory cache, cache store, or RAM cache

L1 cache built in processor

L2 and L3 cache not built in processor

L2 advanced transfer cache most common

Click to view Web Link then click Cache

p. 4.20 Fig. 4-24

Next


MemoryMemory

What is read-only memory (ROM)?

BIOS

(basic input/output system)

Stored on ROM

Sequence of instructions computer follows to load

operating system and other files when you turn on the

computer

ROM is nonvolatile —

Contents not lost when computer is

turned off

Memory chips that contain data, instructions, or information that is recorded permanently

Data can only be read;

cannot be modified in

ROM

Click to view Web Link then click Memory

p. 4.20

Next


MemoryMemory

Types of ROM

PROM

(programmable read-only memory)

Blank ROM on which you can

place items permanently

Firmware

ROM chips manufactured with

permanently written data,

instructions, or information

EEPROM (electrically

erasable programmable read-

only memory)

Type of PROM containing microcode

programmer can erasep. 4.20

Next

MemoryMemory

What is flash memory? Nonvolatile memory that can be erased

electronically and reprogrammed Used with handheld computers and digital

cameras, cellular phones, and automobiles

Click to view video

Click to view Web Link then click Flash Memory

p. 4.21 Fig. 4-25

Next


MemoryMemory

What is CMOS?

Complementary metal-oxide

semiconductor memory

Stores information about

the computer

• type of disk drives• keyboard• monitor• current time and date

Uses battery to retain

information when

computer is turned off

p. 4.21

Next

MemoryMemory

What is memory access time?

Speed at which processor can access data from memory directly

Measured in nanoseconds (ns), which is one billionth of a second

It takes 1/10 of a second to blink your eye; a computer can perform up to 10 million operations in same amount of time

p. 4.22 Fig. 4-26 & 27

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Expansion Slots and Expansion CardsExpansion Slots and Expansion Cards

What is an expansion slot? An opening, or

socket, where circuit board is inserted into motherboard

Expansion card inserted in expansion slot

p. 4.23 Fig. 4-29

Next

expansion card

expansion slot


How are expansion cards used?


then click Expansion Cards

p. 4.23 Fig. 4-28

Next



Computer automatically can configure

cards and other devices as you

install them

What is Plug and Play?

p. 4.24 Fig. 4-29

Next

Credit card-sized device used to add capabilities to notebook computers

PCMCIA - Personal Computer Memory Card International Association

Uses include modem, additional memory, and storage


What is a PC card?

Click to view Web Link then click PC Cards

p. 4.24 Fig. 4-30

Next

PC card



What is a flash memory card? Adds memory to

handheld computers, digital music players, cellular telephones,and similar devices

p. 4.25 Fig. 4-31

Next

PortsPorts

What is a port?

Click to view WebLink then click Ports and Connectors

keyboard

USBUSB

mouse

telephone line in

game port

monitor

svideo out

network

printer (parallel port)

cable TV

speaker

serial port

microphone

telephone line out

FM reception

Connects external devices to system unit

p. 4.25 Fig. 4-32

Next


PortsPorts

What are different types of connectors?

p. 4.26 Fig. 4-34

Next

PortsPorts

What is a serial port?

serial transmission of data

DB-9 female connector

byte representation for number 5 (00110101) byte

representation for number 5 (00110101)

DB-9 male connector

byte representation for number 5 (00110101)

Transmits one bit of data at a time

Used to connect slow-speed devices, such as mouse, keyboard, modem

p. 4.27 Fig. 4-35

Next

PortsPorts

What is a parallel port?byte representation for number 1byte representation for number 3byte representation for number 5

DB-25 male connector

DB-25 female connector

Connects devices that can transfer more than one bit at a time, such as a printer

p. 4.27 Fig. 4-36

Next

PortsPorts

What is a universal serial bus port (USB) ? Connector that

supports newer peripherals and plug and play

Other popular ports include 1394, MIDI, SCSI, and IrDA

p. 4.28 Fig. 4-37

Next

USB port

1394 port

BusesBuses

What is a bus? Channel that allows devices inside

computer to communicate with each other

System bus connects processor and RAM

Bus width determines numberof bits transmitted at one time

Word size determines numberof bits processor can interpretand execute at a given time

Click to view Web Link then click Buses

p. 4.29 Fig. 4-39

Next

system bus

RAM

processor


BusesBuses

What is an expansion bus? Allows processor to communicate with peripherals

fastestnext fastestnext fastestslowest

processor

memory

PCI busexpansion slots ISA bus expansion slots

p. 4.31 Fig. 4-41

Next

BaysBays

What is a bay?DVD-ROM drive

CD-RW drive

Zip drive

empty drive bay

floppy disk drive

Open area inside system unit usedto install additional equipment

p. 4.32 Fig. 4-42

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Some peripheral

devices have AC adapter

Power SupplyPower Supply

What is a power supply?

Converts alternating

current (AC) to direct current

(DC)

p. 4.32

Next

battery

system unit on notebook computer

Floppy disk drive or Zip disk drive

PC Cards in PC Card slots

CD-ROM or DVD-ROM drive

Mobile ComputersMobile Computers

What is a mobile computer?system unit on handheld computer

Notebook, which weighs between 2.5 and 8 pounds, or handheld

p. 4.33 Fig. 4-43

Next


What ports are on a notebook computer?

keyboard/mouse port

IrDA port

serial port parallel port

video portUSB port

p. 4.34 Fig. 4-45

Next


An IrDA port allows the handheld computer to communicate wirelessly with other computers or devices

Handheld computers also can rest in a cradle, so you can transfer data to your desktop computer

How is data transferred from a handheld computer? IrDA port

cradle

p. 4.34 Fig. 4-46

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Pentium® 4 or Athlon™ 600 MHz or higher; or Celeron™ or Duron™ 600 MHz or higher

64 MB RAM

Home MobilePentium® III or AMD-K6® -2-P 500 MHz or higher

64 MB RAM

Putting It All TogetherPutting It All Together

What are suggested processor, clock speed, and RAM requirements based on the needs of various types of users?

Pentium® 4 or Athlon™ 800 MHz or higher

128 MB RAM

Small Office/Home Office Large Business

Pentium® 4 or Athlon™ 700 MHz or higher

128 MB RAM

Pentium® 4 or Itanium™ or Athlon™ 1 GHz or higher

256 MB RAM

Power

p. 4.35 Fig. 4-47

Next

Summary of the Componentsof the System UnitSummary of the Componentsof the System Unit

The system unit Central processing unit Data representation Memory Expansion slots and expansion cards Ports, buses, bays Power supply Mobile computers

Next Chapter 4 CompleteChapter 4 Complete

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